Alien hunters looking for signs of highly-advanced extraterrestrial civilisations might just have found some exciting new evidence – disappearing stars.
The long life cycle of a star can end in a huge explosion, called a supernova, or a violent collapse into a super-dense white dwarf.
What stars do not do, according to our current understanding of stellar evolution, is just disappear altogether.
But a growing number of stars are doing just that. One possible explanation for this mysterious phenomenon is that a super-advanced interplanetary civilisation is building Dyson Spheres.
A Dyson Sphere is a shell-like a gigantic Easter Egg – built around a star. The theoretical megastructure would allow for massive populations to collect almost unlimited clean energy from the star.
Such a construction is impossible with our current level of technology, but a super-advanced culture – what scientists call a Kardashev Type 2 civilisation – might be able to harvest enough material from asteroids or even an entire planet to construct such a shell.
A Dyson sphere would block out a large percentage of the visible light coming from its central star – leading it to ‘disappear’ from an astronomer’s point of view.
And that’s what seems to be happening at the moment. The first example was KIC 8462852, named Tabby’s Star after American astronomer Tabetha S. Boyajian. Its brightness dims apparently randomly, leading some to theorise that a Dyson Sphere is being constructed around it.
There are other explanations; perhaps a constantly-shifting cloud of dense gas or dust, or some cosmic phenomenon that’s new to science.
And now a group of Swedish astronomers have identified up to 100 stars that cannot be accounted for.
A paper published by researchers from the Stockholm University and the Institute of Astrophysics of Canarias says that there are only two explanations; either a brand new type of stellar evolution, or aliens: “Unless a star collapses directly into a black hole, there is no known physical process by which it could physically vanish,” the study reads.
“If such examples exist, this makes it interesting for searches for new exotic phenomena or even signs of technologically advanced civilisations.”
A project to identify these anomalous stars, called The Vanishing & Appearing Sources during a Century of Observations (VASCO), started in 2017
They’ve identified a huge number of stars that dim rapidly, emitting infra-red radiation, and then vanish altogether.
VASCO researchers call these unexplained phenomena ‘red transients.’
One other explanation is that the bright red objects that we’re calling stars could, in fact, be immensely powerful lasers that are being used either for interstellar communication or even as an exotic propulsion method, driving huge solar sails between star systems.
NASA astronomer Joseph Lazio told the Astrobiology Science Conference in June that there are a lot of other stellar anomalies that have raised exciting questions: “If you see a star, say, blinking on and off faster than a microsecond, that’s not obviously a natural phenomenon.”
Humans have wondered for a long time about alien civilisations among the stars, and astronomers seem to be getting ever closer to confirming their existence.